Sat, May 25, 2013, 4:38 PM EDT - U.S. Markets closed
There are 6,820 June Put Options open at a strike price of $15/share.
Another 2,456 at the strike price of $17.50/share.
This is a significant anomaly given the other months low open interest (OI).
It could be that someone is protecting a buy in price of $15-$17.50.
Whatever the reason, it is worth watching.